The present invention pertains to a pre-folding device for carton bottoms. More particularly, the present invention pertains to an apparatus for pre-folding carton bottom flaps for cartons having folded-in gusset tips.
Gable top cartons are widely used for packaging milk, juice and the like. Recently, packaging technology has made enormous strides vis-à-vis these gable top cartons, as well as other types of packages. Present technology permits packaging perishable food items for non-refrigerated extended shelf lives. These packages provide the ability to bring these food items into parts of the world that have limited transportation, distribution and storage infrastructure.
As such, efforts have been focused on increasing the ability to maintain high levels of cleanliness in forming, filling and sealing containers to provide the highest quality product and to provide the greatest product shelf life. In conjunction with these efforts, the demands on packaging machines have become greater, in particular, relative to operating speeds. Such machines must form, fill and seal packages, in a sterile environment, at high operating speeds.
To maintain the integrity of the package after it is filled and sealed, advanced technologies have been applied to the carton materials, as well as the processing operations. Many such packaging materials are formed from paperboard or fiberboard-based materials formed in a composite structure. Typically, one or more layers, such as polymeric coatings, foil coatings and the like, are applied to the paperboard or fiberboard substrate to reduce or eliminate the gas and liquid permeability of the substrate material.
It has been found that one avenue for promoting an environment that reduces the shelf life is wicking of the food product into the package material. Wicking occurs at the edges of the material that are exposed to the food product. Often, wicking occurs at the raw or exposed edges of the bottom wall panels as they are folded to form the bottom wall. To this end, it has been found desirable to reduce the amount or extent of exposed edges, and in particular at the bottom wall. It has also been found that foil at the tips of the gussets (the in-folded triangular panels) can crack thus exposing the paperboard substrate.
One package that has affected such a reduction is disclosed in U.S. Pat. No. 6,328,204 to Stacy-Ryan and an apparatus to form such an over-folded bottom is disclosed in U.S. Pat. No. 6,385,950 to Anderson, both of which patents are commonly assigned with the present application and are incorporated herein by reference. While this over-folded bottom served to “cover” the exposed edge from the bottom front or rear panel, the infolded side panels (those panels that form the triangles when folded in) have edges that can remain exposed.
A package that overcomes these drawbacks is disclosed in copending U.S. patent application Ser. No. 11/163,657, entitled “Carton With Folded-In Gusset Tips”, filed Oct. 26, 2005, commonly owned with the present application and incorporated herein by reference. One machine is known for carrying out the folded in gusset tips of the carton. However, this machine contacts the carton on the interior surfaces to fold the gusset tips after the carton (polymeric coating) has been heated. This resulted in the accumulation of polymer on the folding gusset folding elements which in turn caused increased maintenance.
Accordingly, there exists a need for a carton bottom pre-folding device for pre-folding or pre-breaking cartons having bottoms with folded in gusset tips. Desirably, such a device can be fitted within known form, fill and seal machines. More desirably, such a pre-folding device can accommodate carton folding operations at the operating speeds of known filling machines